A drug for chronic myeloid leukaemia which struggled to gain approval for widespread UK use has proved its worth in long-term clinical trials.
Glivec is a highly targeted drug
The National Institute for health and Clinical Excellence (NICE) initially only wanted Glivec to be given to patients with advanced disease.
However, latest results show around 90% of patients who take the drug survive for at least five years.
Glivec also appears to benefit people with Gastrointestinal Stromal Tumours.
CML is a common form of blood cancer caused by a defect in the production of white blood cells in the bone marrow. Around 600 cases a year are diagnosed in the UK.
Glivec works by precisely targeting the molecules thought to cause the cancer, and leaves healthy cells unaffected.
As a result it has none of the severe side effects associated with current chemotherapy drugs used to treat the condition.
However, it is expensive, costing the health service at least £14,000 per patient per year.
Preliminary guidance from NICE in 2002 suggested Glivec should only be given to a small number of CML patients.
However, following intense lobbying, the institute modified its position to make the drug more widely available by the time it published its final recommendation several months later.
Results from the IRIS study funded by Novartis, the makers of Glivec and the largest study of its kind on adults newly diagnosed with CML, show an estimated 93% of patients taking the drug in the early chronic phase of the disease did not progress to the more advanced stages.
An estimated 83% survived with no evidence of disease progression at all after five years.
Only 4.6% of the patients in the long-term trial died from causes related to their leukaemia
'Saved my life'
Prior to Glivec the disease progressed to an advanced stage - with a very poor prognosis - within four to six years.
The results also showed that the number of patients who responded positively to the drug increased from 69% to 87% between the first and fifth years of treatment.
Sandy Craine, from CML Support, was told that without invasive chemotherapy and a stem cell transplant she had just 12 months to live after being diagnosed as being in the accelerated phase of the disease in 1999.
Ms Craine, who took part in a US trial of the drug, said: "I never would have believed I would be standing here today.
"Glivec helped save my life and I am grateful that I can pass on this message of hope to others diagnosed with this once devastating disease."
Professor Charles Craddock, director of Stem Cell Transplant Unit, Queen Elizabeth Hospital, Birmingham, said: "The significant success of Glivec in treating CML is an exciting model for the development of new treatments for other cancers."
Separate studies have shown Glivec is an effective treatment for patients with advanced Gastrointestinal Stromal Tumours (GISTs).
GIST patients taking Glivec survived for an averages of 58 months, compared with just 15 months with the previous standard chemotherapy treatment.
Dave Cook from GIST Support said: "The data that we have seen today just confirms what I have experienced for myself.
"When six separate GISTs were removed I was devastated, but after four years on Glivec, my scans now show no signs of any abnormality.
"Glivec is a life saver."
Dr Kat Arney, of the charity Cancer Research UK, said: "Glivec has the potential to transform the prospects for people diagnosed with chronic myeloid leukaemia, and may offer hope to many other cancer patients."